The linkage mechanism of a reclining chair controls and coordinates movement of the back, seat, and legrest of the chair during reclining action. In the chair's full upright, or closed, position, the legrest is usually positioned just under the seat and at a right angle to the seat. During conventional reclining action, the back angles backward, the legrest extends and raises, and the front of the seat raises. The action is reversed to return the chair to full upright position.
In some cases, the legrest is stored underneath the seat in a horizontal position. In such a configuration, however, the reclining and inclining action of the chair is similar to that for a configuration where the legrest is at a right angle to the seat.
A three-way reclining chair is one in which the back and seat of the chair move relative to each other during reclining movement. In a two-way reclining chair, the back and seat remain fixed relative to each other at all times. Most reclining chairs employ a single four-bar linkage, a combination of two interactive four-bar linkages, or a six-bar linkage. Linkages are composed of links, a link being a rigid piece, usually a bar or plate. An example of a prior art single four-bar linkage may be found in U.S. Pat. No. 2,968,339 to Hoffman. An example of a prior art dual interactive four-bar linkage may be found in U.S. Pat. No. 3,137,521 to Re. An example of a prior art six-bar linkage may be found in U.S. Pat. No. 3,190,690 to Mizelle.
Conventional reclining chairs are balanced toward a bias of three positions: 1) closed, 2) intermediate recline, and 3) full recline. Since the three positions are preset by the manufacturer, the occupant has no freedom to choose the reclining positions most comfortable for him. Additionally, transition between reclining positions is often abrupt and uncomfortable.
Reclining chairs often require the use of springs or friction devices, or both, somewhere in the linkage to balance the chair in the full upright position, so that it does not recline without some effort put forth by an occupant. With wear of the friction devices, the chair will often recline spontaneously when in its full upright position. This situation is exacerbated when the chair is occupied, since more weight is placed on the back of the chair.
In chairs employing two interactive four-bar linkages, sequencing devices are employed to activate the correct linkages at the proper time during reclining movement. These sequencing devices are often used in addition to springs or friction devices, or both, to help balance and move the chair correctly. All of these devices are often noisy and cumbersome, and add to the cost of manufacture. Some friction devices are also prone to prematurely wear the links to which they are attached.
Another problem with many prior art reclining chairs is the difficulty encountered by an elderly or infirm occupant in entering or exiting the chair. Since the front of such chairs serves as the receptacle of the legrest when the chair is in the closed position, the occupant cannot place his feet directly on the floor beneath him when exiting the chair.
Also, most reclining chairs, especially three-way recliners, have complex linkage systems, resulting in high manufacturing costs and significant maintenance difficulties.
There remains the need for a reclining chair mechanism that overcomes the shortcomings associated with the prior art, as described above.